Encephalartos ngoyanus – Verdoorn (1949)

Ngoye Dwarf cycad (Eng), Ngoye Dwergbroodboom (Afr)

Category: Vulnerable

 

Description


The stem of Encephalartos ngoyanus is subterranean, about 10cm in length and 20cm in diameter. Unless the soil is washed away, the caudex usually does not appear above ground. Unlike that of E. villosus, the caudex never branches or suckers and plants are thus solitary, unless physically damaged. Plants have a thickened root system, though not as tuberous as that of E. caffer.

Each plant bears a crown of 5 to 10 leaves, 0,5m to 1,25m in length. The leaf colour is medium to dark green and the rhachis is straight with the leaflets well spaced. New leaves have silky, wooly hairs, which disappear with age.

Leaflets are reduced in size to the base but rarely to a prickle, leaving a bare petiole of 10cm to 15cm. The median leaflets are 7cm to 8cm long and 9mm to 11mm broad. The leaflets are rarely entire and usually have 1 to 3 teeth on the lower margin.

The cones are solitary and pale olive green at first, turning yellow when mature if grown in the sun. Cones on plants in the shade may retain the original green colour. The male cones are 20cm to 25cm long and 5cm to 7cm in diameter. The median cone scales have the face elongated into a beak 7mm to 8mm long. Female cones are egg shaped, about 25cm long and 10cm to 12cm in diameter. The median cone scales are flattened and slightly overlap the lower ones. Cones in cultivation may exceed these measurements. The seeds are scarlet, 2,5cm to 3cm long and 2cm in diameter. The seeds are longitudinally marked with 8 to 10 sunken grooves. Female cones contain 80 to 100 seeds.

Female cones

Male cones

Leaf detail

Distribution & Habitat


The distribution area of E. ngoyanus extends from the Ngoye forest in the south through the districts of Mtunzini, Mkuze, Ubombo, and Ingwavuma into the southern border of Swaziland and into the Transvaal at Pongola Poort. It occurs in open grassland, as well as on rocky hillsides and in forest margins. The habitat is a summer rainfall area with an annual precipitation varying from 750mm to 1000mm.

Cultivation & Propagation


E. ngoyanus grows well in cultivation but is not a vigorous grower and seldom has more than 8 to 10 leaves in a crown. It is often deciduous before new leaves or cones emerge. It prefers slightly dry conditions and should be grown in full sun. In its habitat they are found growing on steep slopes between boulders indicating its need for good drainage. Seedlings are very prone to damping off and should not be over watered. It is semi hardy to frost and will often lose its leaves particularly on the Highveld. Such dormancy is normal and plants should not be watered when the leaves turn yellow in the autumn. Propagation is by seed only.

 

Notes


Encephalartos ngoyanus was described by Verdoorn in 1949. Prior to that the species had a confused nomenclature. The first recorded name was E. brachyphyllus. Both Medley Wood in 1906 and Chamberlain in 1912, found it growing in close proximity to E. woodii at Ngoye and referred to it as E. brachyphyllus.

E. ngoyanus would appear to be closely related to E. caffer in the Eastern Cape and E. cerinus in Central Natal. E. ngoyanus can be distinguished from E. caffer as follows:

  • The leaflets of E. ngoyanus are usually toothed and seldom entire while those of E. caffer are usually entire and only toothed in the seedling stage.
  • The leaflets of E. ngoyanus are a glossy dark green and the leaflets are well spaced on the rhachis.
  • The leaflets of E. caffer are a soft green, slightly hairy and so numerous that they give a ruffled effect.
  • The leaflets of E. ngoyanus are soft and thin textured even at maturity while those of E. caffer are hardand leathery.
  • The female cone scales of E. ngoyanus overlap the lower ones, while those of E. caffer have a terminal facet.
  • The cones are green at first and turn yellow with maturity.
  • In certain localities the female cone scales of E. ngoyanus are fringed on the lower margin and are almost indistinguishable from those of E. cerinus.

In several localities E. ngoyanus grows socially in very close proximity to other cycad species, notably Stangeria. Inter-generic hybrids are not possible due to the differing chromosome numbers of the genera. In northern Zululand the distribution area of E. ngoyanus overlaps with that of E. lebomboensis but although one would expect natural hybrids, none have been reported in the field. Vorster, however, reports a garden hybrid and states that the resultant F1 cross had long pale green fronds with a slightly waxy bloom. The leaflets were virtually entire and the lower leaflets were not reduced to a series of prickles. Vorster concludes: “From its appearance one would never guess its ancestry. However this is not so surprising because of the phenomenon of cytoplasmic inheritance whereby a hybrid will inherit more characteristics from its female than its male parent.

Although E. ngoyanus is at present classified as “vulnerable” by the Threatened Plant Unit of the IUCN, the species is in need of stringent protection in its habitat. Growing in open grassland, both overgrazing and veld fires have, over the years, taken their toll of the wild populations. Large colonies that used to exist in forest margins and on grassy hillsides can no longer be found. The natural reproduction rate of E. ngoyanus is low compared to other species. In addition over-zealous collectors and commercial interest have latterly removed thousands of specimens. It is difficult to convince a third world population that first world conservation ethics should apply to what they perceive as a commercially exploitable resource. Regrettably, the structures of the law usually apply to the sellers not the buyers who initiate the desecration.